var vecPos:Vector3D = ObjectContainer3D( my.nested.objectContainer3D).sceneTransform.transformVector( new Vector3D(0, 0, 0 ) ) ;

//where Vector3D(0, 0, 0 ) is the local position within the my.nested.objectContainer3D ( for example change second zero to local height of the nested object to get the top of the object )

var spr:Shape = new Shape();
spr.x = (view3D.width / 2) + (vecPos.x);
spr.y = (view3D.height / 2) – (vecPos.y);

- that’s it, now you have 2D coordinates relative to the sprite where you view3D is attached to on.

- An extra note: if you rescale your view3D by setting view3D.width/height after your initial scene setup and you don’t redraw all your objects after that resize then you have to implement the difference in scale versus the original setup of the objects in the formula:

//the view3D size on scene setup
var myInitialView3DWidth = 1000;
var myInitialView3DHeight = 1000;
//now after you resized your view
var myRelativeScaleWidth = view3D.width / myInitialView3DWidth ;
var myRelativeScaleHeight = view3D.height / myInitialView3DHeight ;

var spr:Shape = new Shape();
spr.x = (view3D.width / 2) + (vecPos.x * myRelativeScaleWidth );
spr.y = (view3D.height / 2) – (vecPos.y * myRelativeScaleHeight );

Steve

http://active.tutsplus.com/tutorials/games/pixel-level-collision-detection-based-on-pixel-colors/